Modifying IDT Gamut / Slog2 IDT choices

I’m not really knowledgeable enough to know even if this is possible, but I figured I’d ask away and get educated.

My situation is that I’m shooting in Slog2, and I would like to also use sgamut3.cine. Now, obviously there isn’t a manufacturer-supplied IDT to cover that scenario. Is this something I can mess with, like I would have used LUTcalc to do with a LUT?

Speaking of Sony’s IDTs, I have a few choices and it’s confusing me.

For Slog2, what good will a daylight vs tungsten version of the transform do me if I’m manually white balancing in-camera? Should I just be using the daylight option in that case? There are also 10i and 12i versions; what is the difference here?

I’m sorry if these are really basic questions, but I will feel a lot better about which choices I make in-camera if I can finally get my color where I feel like I have a handle on it.

Well, you could theoretically combine the S-Log2 linearization function w/ the S-Gamut3.cine to AP0 matrix, thus creating a hybrid transform from the two existing CTLs. However, as you yourself note, this is not manufacturer recommended and as such will not be available as a built in transform in any color correction tools (e.g. Resolve, Filmlight, etc). However, support for S-Log2 or S-Log3/S-Gamut3Cine are built in. So I would really question why you feel you must use S-Log2 with S-Gamut3cine?

The differences are in the white balance scale factors and the illuminant used to optimize the color conversion matrix. I would recommend choosing the option that is closest to your capture environment. If daylight is closest, go with that.

10-bit and 12-bit integer. Most implementations beyond the camera are floating point so you shouldn’t really even see this choice in color correctors, etc.

Thanks very much for taking the time to reply.

From my tests the s-gamut3.cine gives a more subdued colour that I prefer. I’m also recording to a 4:2:0 8bit format, so I was thinking that recording in a smaller gamut would be better? I’m extemporizing here; it might not matter one way or the other? Either way, if I want to use Slog2, my hands appear to be tied. No worries.

Sorry, I’m not sure I understand. All other things being equal, recording under an incandescent source vs a daylight source, the camera has been balanced so that the source is neutral; are there still recorded differences that have to be accounted for?

And that explains why I don’t see a choice between the two in Resolve. Thanks very much.